Nature "Crash: A Tale of Two Species" on WXXI-TV

Nature "Crash: A Tale of Two Species" on WXXI-TV

Sun, 05/16/2010 - 8:00pm - 9:00pm
The annual spring spawning of horseshoe crabs produces millions of eggs that are the lifeline for a tiny bird called a red knot (pictured), which migrates 10,000 miles from South America to the Arctic each year.

Credit: ©Mark Peck

NATURE discovers how the plummeting number of horseshoe crabs affects the red knot, a tiny bird. 

The humble horseshoe crab is an evolutionary marvel, virtually unchanged over the course of 350 million years. The small red knot shorebird each year undertakes one of the longest migrations of any species on Earth. The intersection of these two unassuming creatures and our role in their continued survival are shown in breathtaking footage, from the tip of South America to the Arctic, when NATURE “Crash: A Tale of Two Species” encores Sunday, May 16 at 8 p.m. on WXXI-TV (DT 21.1/cable1011 and 11). The film, available in high definition, is produced, written and narrated by Emmy Award-winning filmmaker Allison Argo (“Chimpanzees: An Unnatural History,” “The Urban Elephant”).

“We’re thrilled to work once more with Allison Argo, whose last two films for NATURE have both been recognized with Emmy Awards,” said Fred Kaufman, executive producer of NATURE. “‘Crash’ is a timely story, one that looks at the immediate fate of two amazing, interlinked creatures, as well as the difficult economic factors involved in wildlife conservation.”

Horseshoe crabs’ annual spring spawning on the shores of the Delaware Bay, synched to the new and full moons when tides are highest, produces millions of eggs. The eggs in turn provide an essential refueling stop for the red knot on the nearly 10,000-mile journey from its wintering grounds in Tierra del Fuego to its breeding grounds in the Arctic.

But in the 1990s, while no one was counting, millions of horseshoe crabs were harvested — the preferred bait of booming mid-Atlantic eel and conch fisheries. It was the red knot that sounded the alarm when its numbers began to crash. Some scientists estimate horseshoe crabs in the Delaware Bay have dropped off by 75 percent in the last decade, while the red knot population that winters in Tierra del Fuego has plummeted by 70 percent in the last five years.

The red knots and commercial fishermen aren’t the only ones who depend on horseshoe crabs. They’ve been valued by the biomedical community since the 1970s for their blood, which contains a unique clotting agent that is used in FDA-mandated testing of all intravenous drugs for bacteria. A quart of the crab’s blue blood — it contains copper, not iron — is currently worth about $15,000.

NATURE visits a Charleston, South Carolina, lab where harvested crabs are bled before being released back into the water. The program features scientists in the field who are leading conservation efforts for the red knot and the horseshoe crab; fishermen whose livelihood was affected by a 2006 moratorium on harvesting crabs in the Delaware Bay; and researchers working to develop an artificial bait to replace crabs. “Crash” also offers mesmerizing macro-photography of maturing horseshoe crab embryos. Out of 80,000 eggs that a female lays in a season, 10 or fewer will survive to adulthood.